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K Arita

Publications and source records attributed to K Arita.

At least 91 records · Page 5Linked to original sources
PubMed1997

Usefulness of three-dimensional phase contrast MR angiography on arteriovenous malformations.

Prospective three-dimensional phase contrast (3D-PC) MR angiography was obtained in 34 patients with arteriovenous malformations (AVM) and comparison was made between digital substraction angiography (DSA) and three-dimensional time-of-flight (3D-TOF) methods. Velocity encoding (VENC) for 3D-PC was adjusted to 60 and 10 cm/sec., and was changed only when adequate information was not obtained. VENC 60 cm/sec, demonstrated the main feeders in 100% of cases and the nidus in 86% of cases whereas VENC 10 cm/sec. showed the draining vein in 78% of cases. The detection rate of feeder, nidus and drainer was 60%, 40% and 13% respectively by the TOF technique. The mean size of the nidus as compared with DSA as standard was 130% with MRI, 108% with 3D-PC and 92% with the TOF technique and this difference was not statistically significant. 3D-PC was clearly superior in detecting AVM in the presence of hemosiderin, hematoma or surgical clips. It also showed gradual disappearance of the lesion after radiosurgery. We found 3D-PC superior to 3D-TOF in the diagnosis, therapeutic planning and follow-up of AVM.

Adolescent↗
PubMed1997

Usefulness of two-dimensional time-of-flight MR angiography combined with surface anatomy scanning for convexity lesions.

Thirty-eight patients with convexity lesions were studied prospectively with the two-dimensional time-of-flight (2D-TOF) magnetic resonance angiography (MRA) method. Of these 21 cases had additional surface anatomy scanning (SAS) and 7 cases had three-dimensional phase contrast (3D-PC) MRA. The findings were compared during surgery and the predictability of 2D-TOF evaluated. 2D-TOF was obtained with 2 mm slice thickness after the administration of contrast media for routine magnetic resonance imaging (MRI). Cortical veins were visualized with a good resolution with a scan time of only 5 minutes. The tumor was also visible in the background, due to enhancement, and thus the tumor-vessels relation was shown. Slow-flow vessels were also adequately seen. SAS was done at the same sitting with fast spin echo (FSE) with a scan time of 3 minutes. Once both images were incorporated, information on gyri and their relation to the lesions and vasculature could be obtained from a single image. We found 2D-TOF alone, or at times in combination with SAS, useful for planning of operation for convexity lesions.

Adolescent↗
PubMed1997

Incidence of intracranial aneurysm associated with pituitary adenoma.

The incidence of intracranial aneurysm associated with pituitary adenoma is not definitely established although reported higher than in general population. This study was designed to find the existence of such association in a large series of pituitary adenoma cases. A retrospective study of 467 cases of pituitary adenoma (mean age: 41 +/- 15 years) was done. All patients underwent cerebral angiography at least of anterior circulation, detailed hormonal study, and 155 cases had additional magnetic resonance (MR) angiography. Twenty-five cases (5.4%) of pituitary adenoma (mean age 52 years) had intracranial aneurysm, 97% on anterior circulation, and 12% had multiple aneurysms. Two cases presented with aneurysmal rupture and the rest were incidental. Aneurysm was more frequently seen with increasing age (p < 0.001) and the age distribution resembled that of aneurysm among general population. Although the combination was most frequent among nonfunctioning adenoma (8.8%), and least frequent among prolactinoma (2.4%), this association was again due to age factor. There was no association between hormone secretion, size and invasive nature of the tumor. The results showed no association between intracranial aneurysm and pituitary adenoma. Our speculation is that such occurrence is merely a chance factor and the risk is no greater than that among general population.

Adenoma↗
PubMed1997

MIB1 immunopositivity is associated with rapid regrowth of pituitary adenomas.

Pituitary adenomas are generally regarded as benign tumours, but they may recur. We identified eight patients with pituitary adenomas that showed rapid regrowth within 2 years of initial surgery. We estimated the percentage of cells in each specimen that showed positive immunostaining for MIB1 (a novel anti-Ki-67) and compared the values to those of 40 adenomas that showed no regrowth. The mean MIB1 index for 40 adenomas that showed no evidence of regrowth was 0.19 +/- 0.06%. This was significantly (p < 0.0001) lower than that for adenomas that showed rapid regrowth (1.27 +/- 0.31%), based on the initial resected specimens. Immediately after detection of rapid regrowth and in adenomas that were resistant to bromocriptine or irradiation, the MIB1 index was always greater than 1.0%. Most patients with rapidly regrowing adenomas were well controlled by radiation therapy. Our results suggest that a MIB1 index greater than 1.0% may be a useful predictor of rapid regrowth of pituitary adenomas and may be useful for planning of therapy.

Adenoma↗
PubMed1997

Fluid-attenuated inversion recovery (FLAIR) in a patient with parasagittal white matter shearing injury.

We present a 32-year-old woman with a parasagittal white matter shearing injury of the left frontal lobe following a motor vehicle collision. There was monoplegia of the right lower extremity. Computed tomography failed to demonstrate the lesion which was visible on magnetic resonance images. In particular, fluid-attenuated inversion recovery images were useful to depict the shearing injury, since sulci were of low intensity on those images.

Adult↗
PubMed1997

Evaluation of cerebral hemodynamics in a head-injured patient with hypovolemia using transcranial Doppler sonography.

A 20-year-old man presented with hypovolemic shock caused by abdominal injury. Cerebral hemodynamics were evaluated by transcranial Doppler (TCD) sonography. Middle cerebral artery flow velocities decreased, and the pulsatility indices increased markedly. Particularly, the waveform of the left middle cerebral artery showed a systolic peak, suggesting an increased intracranial pressure. Actual intracranial pressure was 7 mm Hg, and the cerebral perfusion pressure (CPP) was 51 mm Hg. These abnormal Doppler signals seemed to be caused by a compromise in CPP and to be aggravated by hypovolemia. The patient was discharged with a residual mild memory disturbance. Hypovolemia aggravates a reduced cerebral blood flow caused by a compromised CPP, and the waveform of TCD in a case of hypovolemic shock should be differentiated from intracranial hypertension.

Accidents, Traffic↗
PubMed1997

Expression of epithelial cadherin and cavernous sinus invasion in human pituitary adenomas.

Pituitary adenomas generally are regarded as benign tumors, although some invade the cavernous sinus and recur. We examined the epithelial cadherin (E-CD) expression in 30 pituitary adenomas (6 with cavernous sinus invasion and 24 without). Immunoreactivity of E-CD were found in all pituitary adenomas but they were very various. The presence of an association between E-CD expression and cavernous sinus invasion was assessed. There were no significant differences in E-CD expression between invasive and noninvasive adenomas. These results suggest that E-CD expression is not associated with cavernous sinus invasion in pituitary adenomas.

Adenoma↗
PubMed1997

Delayed hyperemia causing intracranial hypertension after cardiopulmonary resuscitation.

OBJECTIVE: To clarify whether early or delayed failure of cerebral perfusion after cardiopulmonary resuscitation (CPR) occurs in humans and contributes to secondary brain damage. DESIGN: Prospective, repeated-measures study. SETTING: Intensive care unit of Hiroshima University School of Medicine. PATIENTS: Eight comatose patients who had undergone successful resuscitation from cardiac arrest. INTERVENTIONS: All patients underwent transcranial Doppler sonography examination. The intracranial cerebral pressure (ICP) and jugular venous oxygen saturation (SO2) also were continuously monitored in five patients and three patients, respectively. MEASUREMENTS AND MAIN RESULTS: In each patient, we measured the mean flow velocity of the middle cerebral artery transcranially and the mean flow velocity of the internal carotid artery, high in the neck, using transcranial Doppler sonography. The pulsatility index for each measurement was also calculated. The first examinations were performed within 4 to 12 hrs of CPR, and repeat examinations were performed approximately every 12 hrs. The initial mean flow velocities of the middle cerebral artery and the initial mean flow velocities of the internal carotid artery were relatively low, with relatively high pulsatility indices. The mean flow velocities of the middle cerebral artery began to increase at 12 to 24 hrs after CPR and peaked 24 to 120 hrs after CPR. A simultaneous increase in mean flow velocities of the internal carotid artery was observed during this period. The pulsatility index in both arteries dropped significantly during peak mean flow velocity of the middle cerebral artery. In six of seven patients with an abnormal increase (> 100 cm/ sec) in peak mean flow velocity of the middle cerebral artery, the ratio of mean flow velocity of the middle cerebral artery to mean flow velocity of the internal carotid artery was < 3. This value tended to be lower in patients with poor outcomes. An increased mean flow velocity of the middle cerebral artery, with a ratio of < 3 for mean flow velocity of the middle cerebral artery to mean flow velocity of the internal carotid artery, was defined as hyperemia. Although the mean flow velocity of the internal carotid artery was not measured, another patient with an abnormal increase in mean flow velocity of the middle cerebral artery revealed a high jugular venous SO2 value of 83.5%, also representing hyperemia. All ICP values were within the normal range 4 to 12 hrs after CPR and tended to increase before peak mean flow velocity of the middle cerebral artery. The two patients with the lowest ratios of mean flow velocity of the middle cerebral artery to mean flow velocity of the internal carotid artery showed significant increases in ICP after the peak mean flow velocity of the middle cerebral artery. These two patients subsequently developed brain death. CONCLUSIONS: Delayed hyperemia occurs in humans after resuscitation from cardiac arrest. Our data suggest that this delayed hyperemia can lead to intracranial hypertension and occasionally acute brain swelling, contributing to a poor outcome. A high mean flow velocity of the middle cerebral artery with a low ratio of mean flow velocity of the middle cerebral artery to mean flow velocity of the internal carotid artery may be predictive of critical hyperemia. As an indirect method of measuring cerebral blood flow transcranial Doppler sonography can be used to adjust treatment for failure of cerebral perfusion after resuscitation.

Blood Flow Velocity↗
PubMed1997

Cerebral fat embolism studied by magnetic resonance imaging, transcranial Doppler sonography, and single photon emission computed tomography: case report.

Cerebral fat embolism syndrome is an uncommon complication of trauma. We present a patient who developed cerebral fat embolism syndrome secondary to long-bone fractures. Although computed tomography of the brain failed to show any intracranial lesion, magnetic resonance imaging (MRI) detected scattered, high-signal-intensity lesions on T2-weighted images. 99mTc-d, 1-hexamethyl-propylene amine oxine single photon emission computed tomography (99mTc-HMPAO SPECT) and transcranial Doppler sonography (TCD) demonstrated low cerebral blood flow in the acute stage. MRI, 99mTc-HMPAO SPECT, and TCD correlated well with the clinical course of cerebral fat embolism syndrome.

Adult↗
PubMed1997

Antiepileptic effects of 20-hydroxyecdysone on convulsive seizures in spontaneously epileptic rats.

We examined the effect of 20-hydroxyecdysone (20-HE), a neurosteroid found in insects that is involved in their developmental process, on both tonic convulsion and absence-like seizure in spontaneously epileptic rat (SER). When 20-HE was given orally to SER at 25-200 mg/kg, significant decreases of the tonic convulsion were observed with 100 and 200 mg/kg. Pretreatment of the animal with bicuculline (1 mg/kg, i.p.) antagonized the inhibitory effects of 20-HE. However, absence-like seizures were not affected by 20-HE. These findings indicate that 20-HE produces antiepileptic effects on tonic convulsion by acting on the modulatory site of GABA(A) receptors.

Administration, Oral↗
PubMed1997

Development of a CAI program entitled 'Introduction to Nursing Process'. Requirement for nursing education in Japan.

A new teaching strategy is required in nursing education in Japan. A multimedia CAI (Computer Assisted Instruction) program entitled "Introduction to Nursing Process." was developed. The aim of this study was to examine whether CAI could assist students' knowledge acquisition, and increase their motivation and readiness to learn clinical nursing practice. This study involved the process of developing CAI and a pilot study for measuring and evaluating the CAI program. Results demonstrate that CAI can increase students' understanding about the nursing process, enhance their motivation to learn, and provide realistic situations describing the concept of nursing the process.

Computer-Assisted Instruction↗
PubMed1997

[A case of cerebral arteriovenous malformation with accidental migration of a microcatheter during endovascular procedure].

This is a report of a case of cerebral arteriovenous malformation with accidental breakaway of a microcatheter during endovascular embolization. A 25-year-old female suddenly suffered severe headache. CT scan demonstrated intraventricular hemorrhage, and the angiogram revealed right parieto-occipital AVM. We performed endovascular embolization using a flow-directed microcatheter (1.5F BALT MAGIC catheter) 2 weeks after onset, and the microcatheter broke accidentally and a fragment of the soft tip migrated to the distal posterior cerebral artery during the procedure. Although we tried to retrieve the catheter using several retrieval devices, we failed. Two days after the procedure we undertook surgical treatment. The migrated catheter was recognized in a small feeding artery which was stretched tightly, so retrieval was very risky. Using hemoclips for trapping the part of the catheter which remained in the feeder, we were able to retrieve it by cutting the feeder. Flow-directed microcatheters are very usefull in endovascular procedures, but it is necessary to handle them carefully in accord with sufficient knowledge of their use and handling methods.

Adult↗
PubMed1996

Diagnosis of carotid-cavernous fistulas with magnetic resonance angiography--demonstrating the draining veins utilizing 3-D time-of-flight and 3-D phase-contrast techniques.

This study assessed the ability to diagnose carotid-cavernous fistulas (CCFs) non-invasively using magnetic resonance angiography (MRA). Both three-dimensional time-of-flight (3-D TOF) MRA and three-dimensional phase-contrast (3-D PC) MRA were compared with conventional cerebral angiography in nine patients with CCFs. CCFs were grouped according to Barrow's classification. In all cases, 3-D TOF MRA revealed an inferior petrosal sinus as a draining vein. 3-D PC MRA demonstrated a dilated and tortuous superior ophthalmic vein (SOV) and reflux of the SOV in seven patients. In conclusion, CCFs can be diagnosed with MRA alone by demonstrating the drainging veins.

Adult↗
PubMed1996

Matrix metalloproteinase-9 secretion by human pituitary adenomas detected by cell immunoblot analysis.

Twenty-two pituitary adenomas were examined on the secretion of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) using a cell immunoblot assay, and discussed regarding an association between cavernous sinus invasion and the secretion of these proteins. The cell immunoblot assay, a kind of immunoblot procedure, is able to detect proteins at the single cell level and to detect the incidence of tumour cells secreting the target proteins in the total tumour cell population. The incidence of tumour cells secreting MMP-9 was significantly higher in invasive adenomas than in noninvasive ones. On the other hand, TIMP-1 secretion was not detected in any adenomas in this study. This result suggested that MMP-9 secretion, and especially the number of MMP-9-secreting cells, may be associated with cavernous sinus invasion of pituitary adenomas.

Adenoma↗
PubMed1996

Type IV collagenase activity and cavernous sinus invasion in human pituitary adenomas.

Pituitary adenomas are regarded generally as benign tumours, but some of them can invade the cavernous sinus. On the other hand, matrix metalloproteinase-9 (MMP-9), which is a type IV collagenase, recently has been found to be expressed in matastases and to be related to the invasiveness of various malignant tumours including brain tumours. In order to investigate some characteristic features of pituitary adenomas which invade the cavernous sinus, we examined immunohistological studies for MMP-9 in seven pituitary adenomas for type IV collagen in a dura mater and assayed for type IV collagenase activity in seven adenomas using type IV collagen labelled with fluorescein isothiocyaniate (FITC). We found immunopositive adenoma cells for MMP-9 in all invasive adenoma and immunopositive spindle like cells for type IV collagen in the dura mater. All three invasive adenomas had high levels of type IV collagenase activity (0.57-0.72 U/ml), but the four adenomas which did not invade the cavernous sinus had low levels of type IV collagenase activity (0.0-0.10 U/ml). These results suggest that the level of type IV collagenase activity in a pituitary adenoma may be related to its ability to invade the cavernous sinus.

Adenoma↗
PubMed1996

Endoscopic resection of intraventricular ependymal cyst presenting with psychosis.

BACKGROUND: Intracranial ependymal cysts are rare lesions generally located in the cerebral parenchyma, juxtraventricular region, or subarachnoid space; but no case of a purely intraventricular ependymal cyst has been reported. CASE REPORT: A case of intraventricular ependymal cyst presenting with symptoms of psychosis is reported. The patient's symptoms resolved almost completely following endoscopic resection of the cyst. The embryologic basis of the development of an ependymal cyst inside the ventricle and its histologic characteristics are discussed. Possible mechanism of psychosis in this case is also discussed. CONCLUSION: Minimally invasive techniques, as in this case, may be useful in refractory psychotic cases with cystic lesions.

Adult↗